Steam generator



Oct. 18, 1932. H. J, KERR E1' Al.

STEAM GENERATOR Original Filed Maron 22. 1927 2 sheets-sheet 2 INVENTORJ ATTORNEYS Patented Oct. 18, 1932 UNITED STATES PATENT OFFICE HOWARD J'. IKERR, OF WESTFIELD, NEW JERSEY, AND JAMES FLETCHER, OF WEST NEW BRIGHTON, NEW YORK, ASSIGNORS T THE BABCOCK 8c WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY STEAM GENERATOR Application led Harch 22, 1927, Serial No. 177,256. Renewed June 3, 1932.

This invention relates to a steam generator I in which water may be recirculatedthrough a series of tubes and flows through a number of other tubes by natural or gravity circulation. The invention will be understood from the description in connection with the accompanying drawings, in which Fig. 1 shows a vertical section through an illustrative embodiment of the invention; Fig. 2 shows a similar section through a modification and Fig. 3 is a section on an enlarged scale, partly broken away, taken along the line 3-3 of Fig. -2. In the drawings, reference character 5 indicates a furnace which may, for example, be heated by means of the burners 6. This furnace is provided with a rear wall 7, behind which a vertically disposed flue 8 for hot gases is provided. A passage 9 leads from the lower end of the flue 8 to the flue 10, from which the outlet 1l opens.

A number of horizontally disposed U-tubes Y 15 are located in the flue 8 and extend thereacross. The ends of these tubes are connected to headers 16, which form one side of the flue 8. The lowermost header 16u has a valved pipe17 connected thereto, which pipe leads from the feed water pum 18 connected to any convenient source of eed water supply.

The tubes 19 lead from the uppermost header 16 to the steam and water drum 20,

which is provided with a water level gauge y water drum 20 to the steam main.

The operation is as follows: Hot products lowermost header 16", from whence it passes through the tubes 15 upwardly in succession to the topmost header 16, thence through the tubes 19 to the steam and water drum 20 where the steam and water are separated, The water in the steam and water drum 20 circulates by natural or gravity circulation through the tubes 22 between the drums 20 and 23. Tubes outside of the furnace walls may also connect the drums 20 and 23 as shown in Fig. 3 to aid the natural circulation if desired. It will be noticed that the hot gases first contact with the bank of tubes 22 and then contact with the tubes 15 in countercurrent direction with respect to the flow of water through the tubes 15.

The connection 25 makes it possible to circulate water throu h the series tubes 15 while starting up. T 's may take place by natural circulation when the hand valve 27 is open as the hot lWater in the tubes 15 will rise and the cooler water will descend from the drum 20 through connection 25 outside of the furnace wall to the lowermost header 16a, the check valve 28 preventing reverse flow.

The saine connection 25 makes it possible to recirculate a portion of the water within the boiler through the series tubes 15. Forced circulation of the water passing through connection 25 to the series section may also be produced at any time by means of the pump 26 that may be driven in any convenient manner.

If desired, the connection 25 may be connected td an intermediate point in the `series section, instead of to the lowermost header 16a, in which case the water returned from the drum 20 passes again through only a portion of the series section. y

In the modification shown in Figs. 2 and 3, parts similar to -those shown in Fig. 1 are designated by the same reference characters with primes, and it is not thought necessary of combustion from the furnace 5 passupto describe these parts again in detail. In

wardly across the bank of tubes 22, thence over the drum 23 and downwardly through the flue 8 in contact with the tubes 15, thence outwardly through the passage 9, Hue 10 and 'outlet 11. Feed water is forced by means of the pump 18 through the pipe 17 into the this modification, natural or gravity circulation tubes connect the drums 20 and 23. The tubes 22 connecting the drum 20' to the drum 23 are made larger than the tubes 19 and are spaced apart considerabledistances, so as to provide a slag screen for the hot products of combustion that impinge a ainst these tubes. The tubes 22a outside o the furnace connect the drum 20 to the drum 23 to aid the natural circulation.

As indicated in Fig. 2, the valve 27 may be provided with a thermostatic device which will automatically open this valve to permit circulation of water from drum 20 through the tubes 15 in case the tubes 15 become too hot, for example when the supply of feed water is cut olf. A valved pipe 30 is shown in Fig. 2 by which a portion or all of the. feed water may be passed directly from the pump 18 to the drum 20 without passing through the tubes 15.

A bypass connection 81 provided with a valve 32 may be provided between the uppermost header 16 and an intermediate header, this bypass connection being preferably located outside of the furnace wall. When the valve 32 is open this connection 31 provides a local circulation through the upper tubes 15 and headers 16 that are contacted by the hotter gases, thu-s decreasing the danger of having these tubes burned out, especially when putting the boiler into service.

In both modifications the tubes connecting the drums are located below the portions of the series tubes that enter the steam and water drum and are larger and spaced farther apart than the series tubes. The hot gases from the furnace 5 contact first with the larger tubes or natural circulation tubes which form slag screens to protect the other tubesand prevent the accumulation of slag thereon.

\ We claim:

1. In a steam boiler, a plurality of tubes connected in series, a steam and water drum connected to the tubes at one end of said series, means for feeding water into the tubes at the other end of said series, means including a ump that will permit passage of water theret rough by gravity for returning water from said drum to the feed water end of said series, a second drum, and tubes conneoting said drums.

2. In a steam boiler, a plurality of tubes connected in series, the upper tubes of said series being longer than the lower tubes, a steam and water drum connected to the upper tubes of said series, means for feeding water into the lower tubes of said series, means including a pump that will permit passage' of water therethrough by gravity for returning water from said drum to said tubes, a second drum, and tubes connecting said drums.

3. VIn a steam boiler, a plurality of tubes connected in series, a steam and water drum connected to the upper tubes of said series, means for feeding water into the lower tubes of sa1d series, means including a pump that will permit passage of water therethrough by gravlty for returning water from said drum to said lower tubes, a second drum, tubes connecting said drums. and means to pass hot gases downwardly across said series tubes.

4. In a steam boiler, a plurality of tubes connected in series, a steam and water drum connected to the tubes at one end of said series, a second drum, tubes connecting said drums, thel connection from said seriesl to said drum being above the highest tubes connecting said drums, and means for passing hot gases across said last named tubes and then across said first named tubes.

5. In a steam boiler, a plurality of tubes connected in series, a steam and water drum connected to the tubes at one end of said series, a second drum, tubes connecting said drums the connection from said series to said drum being above the highest tubes connecting said drums, said last named tubes being larger and spaced farther apart than the series tubes and located in the path of gas flow below the portions thereof that enter the steam and water drum.

HOWARD J. KEER. JAMES FLETCHER. 

